The American lobster (<em>Homarus americanus</em>) plays an integral role in the coastal Northwest Atlantic as a benthic consumer and the target of the most valuable single-species fishery in North America. In the past decade, benthic recruitment of juvenile lobster has declined, even as egg production has increased, suggesting heightening levels of larval mortality. Recent correlative studies in the Gulf of Maine further suggest early-stage larval survival may be related to the supply composition of planktonic foods. Despite these correlative studies and the economic importance of the species, relatively little is yet known about how larval lobsters interact with their prey in the pelagic environment. As development progresses through the four planktonic larval and postlarval stages, the young lobsters rely heavily upon zooplankton for food. During these early developmental stages, lobster larvae undergo significant morphological changes. This study used a combination of laboratory-based feeding experiments and video recordings to examine changes in feeding behavior and ingestion rates between larval stages. We observed dramatic stage-to-stage improvements in the capacity to pursue, capture, handle, and ingest specific prey, especially after the metamorphosis to the postlarval stage. The results highlight the vulnerability of the early life stages to low food densities. They also elucidated differences in the ability of specific prey taxa to evade predation. Quantifying the interactions between larval lobsters and their prey enhances our understanding of how larvae interact with the pelagic food web, the fraction of available zooplankton representing viable food sources, and how lobster larvae may be impacted by altered prey availability associated with climate change.

Primary Presenter: Evelyn Layland, University of Maine (evelyn.layland@maine.edu)

Authors:

Evelyn Layland, University of Maine  (evelyn.layland@maine.edu)

Molly Spencer, University of Southern Maine  ()

Emily Patrick, University of Maine  ()

Rachel Lasley-Rasher, University of Southern Maine  ()

Richard Wahle, University of Maine  (richard.wahle@maine.edu)

David Fields, Bigelow Laboratory for Ocean Sciences  (dfields@bigelow.org)